The present invention relates to a prediction method and system capable of predicting rapid motion in the earth""s crust, such as a volcanic eruption, an earthquake, a landslide and ground collapse, by sensing a precursory phenomenon on the basis of an electromagnetic field observation.
For the prediction of volcanic eruptions, earthquakes, landslides, ground collapse, etc., it is most important to capture precursory phenomena. In studies and research conducted so far, promising precursory phenomena relating to diastrophism and seismic activities have been reported, and methods and systems for measuring such precursory phenomena have been proposed. However, a decisive precursory phenomenon has not yet been found, and there has been proposed no effective system for measuring such a precursory phenomenon. Meanwhile, it has recently become clear that underground fluids, e.g. groundwater and magma, fundamentally play an important role in causing such phenomena in the earth""s crust. However, no attempts have been made to capture precursory phenomena by positively utilizing the knowledge of this fact and to make use of the precursory phenomena to minimize disasters that accompany earthquakes, volcanic eruptions, ground collapse, etc.
In view of the above-described problems, an object of the present invention is to make it possible to predict rapid motion in the earth""s crust by sensing a precursory phenomenon with a simple method and system.
To attain the above-described object, the present invention provides a prediction method of predicting rapid motion in the earth""s crust, such as a volcanic eruption, an earthquake, a landslide and ground collapse, wherein an electromagnetic field is measured in or near a confined aquifer in which groundwater is stored and flows, and motion of ground pore water is sensed on the basis of the measured electromagnetic field to predict rapid motion in the earth""s crust. Preferably, the measurement of the electromagnetic field is performed at the distal end of a casing pipe inserted into a drilled hole.
In addition, the present invention provides a prediction system for predicting rapid motion in the earth""s crust, such as a volcanic eruption, an earthquake, a landslide and ground collapse. The system includes a casing pipe inserted into a drilled hole reaching the inside of a confined aquifer in which groundwater is stored and flows or a position near the confined aquifer. A measuring device measures an electromagnetic field at the distal end of the casing pipe. An analyzing device analyzes data concerning the electromagnetic field measured by the measuring device to sense motion of ground pore water, thereby predicting rapid motion in the earth""s crust. Preferably, the casing pipe is an electrically conductive pipe having a non-magnetic screen portion formed at the distal end thereof so that recycling groundwater passes through the screen portion, and the measuring device includes an electromagnetic field sensor placed in the screen portion. The measuring device may include the conductive casing pipe as an electrode for measuring an electric potential relative to an electric potential at the earth""s surface detected with a reference electrode.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention accordingly comprises the features of construction, combinations of elements, and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.